1. Field of the Invention
The present invention relates generally to automatic translating machines for translating a sentence in a source language into a sentence in a target language, and more specifically, to an automatic translating machine permitting a user to select the most appropriate translation of a sentence which can be translated in several ways.
2. Description of the Related Art
One example of a conventional automatic translating machine is disclosed in Japanese Patent Laying-Open No. 63-136266. As disclosed in this document, the conventional translating machine includes a morphological analysis portion for segmenting an input sentence into morphemes utilizing a dictionary thereby providing information such as part of speech, a syntactic analysis portion for analyzing the syntax of a morpheme string decomposed by the morphological analysis portion utilizing a dictionary and grammatical rules thereby providing a syntactic structure (parsing tree), a transformation portion for transforming the syntactic structure provided at the syntactic analysis portion into a syntactic structure in a target language, and a translated sentence producing portion for producing a translated sentence according to the syntactic structure in the target language provided by the transformation portion.
A disadvantage encountered in such a translating machine is that the input sentence can be interpreted in many ways because of ambiguity in the input sentence such that several translated sentences are produced. It is therefore necessary to select one of the obtained plurality of translated sentence that reflects the count meaning of the original sentence. Therefore in some cases translated sentences produced by the translated sentence producing portion are displayed on a picture frame one after another in response to an operator and then selection of a suitable translated sentence is left solely to the discretion of the operator. In other cases, the translated sentence producing portion produces several translated sentences according to the number of interpretations to display the resultant sentences on the picture frame at one time for permitting the operator to select the most suitable one from the group.
If, for example, the following English sentence is input as an input original sentence, roughly six translated sentences follows from the ambiguity of the original sentence itself. Of course the accuracy of translation in this case depends on the grammatical processing capability of a translating machine performing the translation and the level of dictionaries equipped to the machine. The following example is therefore only a general example.
TABLE 1 ______________________________________ [Original] I gave the cat food, and put the block in the box on the table. [Translation 1] , [Translation 2] , [Translation 3] , [Translation 4] , [Translation 5] , [Translation 6] , ______________________________________
The six different translations are provided for the following reason, In analysis of the syntax of the input sentence by the syntactic analysis portion, grammatical rules as shown in Table 2 are applied.
TABLE 2 ______________________________________ (a) Sentence .fwdarw. declarative sentence sentence end (b) declarative sentence .fwdarw. declarative sentence comma conjunction declarative sentence (c) declarative sentence .fwdarw. noun phrase verbal phrase (d) declarative sentence .fwdarw. verbal phrase (e) noun phrase .fwdarw. noun phrase prepositional phase (f) noun phrase .fwdarw. noun (g) noun phrase .fwdarw. article noun (h) noun phrase .fwdarw. article noun noun (i) prepositional phrase .fwdarw. preposition noun phrase (j) verbal phrase .fwdarw. verb noun phrase (k) verbal phrase .fwdarw. verb noun phrase prepositional phrase (1) verbal phrase .fwdarw. verb noun phrase noun phrase ______________________________________
Referring to Table 2, rule (a), for example, indicates that "a sentence is formed of a declarative sentence and a sentence end", while rule (e) indicates that "a noun phrase is formed of a noun phrase and a prepositional phrase". Rules (e)-(h) each define a noun phrase, anything satisfying the right term of each rule is interpreted as a noun phrase. As indicated by rules (j) and (k), this applies to the case of a verbal phrase.
Since a plurality of grammatical rules can be applied to a noun phrase or a verbal phrase as described above, two interpretations are possible for the first underlined part of the Original Sentence, while three interpretations are possible for the second underlined part. As a result, 2.times.3=6 interpretations in total are generated for the Original Sentence.
Conventionally, these six translated sentences are displayed one after another, and a desired translated sentence displayed is selected or alternatively the operator selects one of the six translated sentences collectively displayed.
Suppose that the user intends to select translated sentence 5 from the above-described six translated sentences obtained. If the sentences are displayed in the order of translated sentences 1, 2, . . . the display would have to be switched at least four times until the desired translated sentence is displayed. If translated sentence 1 and translated sentence 5 are compared, the desired translation is already obtained for the first underlined part, and only the second underlined part should be translated differently. However, alternative translation candidates are displayed for the first underlined part as in translated sentences 2 and 4, and the work efficiency is not high in selection. If six kinds of interpretations exist as described above, all the translated sentences can be displayed by switching only five times. However, if the original sentence is complicated and long, a large number of interpretations will be obtained for the sentence, and therefore prolonging the time required for the selection operation.
In Laid-Open Japanese Patent No. 63-136266 described above, the sequentially displayed translated sentences are stored in a buffer. As a result, the translated system may be displayed in the reversed sequence by operating a special key, so that even if the operator skips an appropriate translated sentence, he/she can easily go back to the appropriate translated sentence. However, this method is not a fundamental solution to simplification of the selection process in the presence of a large number of possible translations as described above.
Similarly, the approach of displaying all the possible translations at one time on the picture frame has the following disadvantage. If an original sentence is complicated and long, the number of translated sentences obtained will be large as described above. Therefore, that large number of translated sentences cannot be displayed on one picture frame, and therefore it would be necessary to display them by switching. Furthermore, since the number of displayed translated sentences is large based on all the possibilities, it would be difficult to identify the appropriate translated sentence from the large number of sentences.
In order to solve such a disadvantage, a method is considered by which a user designates a prescribed range of an original sentence referring to the displayed translated sentences, and translation is performed based on different interpretations only within the designated range. Even if such a method is employed, however, the user cannot know which grammatical rule is applied to the original sentence nor how the sentence is segmented into phrases by the machine. Therefore, it is very much difficult for the user to accurately select a range in the original sentence in order to obtain a correct translation.